well it's tough to describe. It's not a matter functionality since the OC2 is obviously simple. But the tone you get seems "weightier" + "juicier" for the lack of a better term.
Off course it has something to do with how the octave is voiced, and I dont see any way of changing that in the Helix. If you know the OC2 on bass and knows how to make the Helix sound like that, I would appreciate your suggestions.
Even better, make a model that gets the tone. I'm sure you can :-)